Gastroenterology

Gastroenterology

Volume 153, Issue 3, September 2017, Pages 732-742.e1
Gastroenterology

Original Research
Full Report: Clinical—Alimentary Tract
Risk Stratification for Covert Invasive Cancer Among Patients Referred for Colonic Endoscopic Mucosal Resection: A Large Multicenter Cohort

https://doi.org/10.1053/j.gastro.2017.05.047Get rights and content

Background & Aims

Among patients with large colorectal sessile polyps or laterally spreading lesions, it is important to identify those at risk for submucosal invasive cancer (SMIC). Lesions with overt endoscopic evidence of SMIC are referred for surgery, although those without these features might still contain SMIC that is not visible on endoscopic inspection (covert SMIC). Lesions with a high covert SMIC risk might be better suited for endoscopic submucosal dissection than for endoscopic mucosal resection (EMR). We analyzed a group of patients with large colon lesions to identify factors associated with SMIC, and examined lesions without overt endoscopic high-risk signs to determine factors associated with covert SMIC.

Methods

We performed a prospective cohort study of consecutive patients referred for EMR of large sessile or flat colorectal polyps or laterally spreading lesions (≥20 mm) at academic hospitals in Australia from September 2008 through September 2016. We collected data on patient and lesion characteristics, outcomes of procedures, and histology findings. We excluded serrated lesions from the analysis of covert SMIC due to their distinct phenotype and biologic features.

Results

We analyzed 2277 lesions (mean size, 36.9 mm) from 2106 patients (mean age, 67.7 years; 53.2% male). SMIC was evident in 171 lesions (7.6%). Factors associated with SMIC included Kudo pit pattern V, a depressed component (0–IIc), rectosigmoid location, 0–Is or 0–IIa+Is Paris classification, non-granular surface morphology, and increasing size. After exclusion of lesions that were obviously SMIC or serrated, factors associated with covert SMIC were rectosigmoid location (odds ratio, 1.87; P = .01), combined Paris classification, surface morphology (odds ratios, 3.96−22.5), and increasing size (odds ratio, 1.16/10 mm; P = .012).

Conclusions

In a prospective study of 2106 patients who underwent EMR for large sessile or flat colorectal polyps or laterally spreading lesions, we associated rectosigmoid location, combined Paris classification and surface morphology, and increasing size with increased risk for covert malignancy. Rectosigmoid 0–Is and 0–IIa+Is non-granular lesions have a high risk for malignancy, whereas proximally located 0–Is or 0–IIa granular lesions have a low risk. These findings can be used to inform decisions on which patients should undergo endoscopic submucosal dissection, EMR, or surgery. ClinicalTrials.gov, Number: NCT02000141.

Section snippets

Materials and Methods

Prospective, observational, multicenter data on consecutive patients referred to 1 of 8 Australian academic hospitals for the management of large sessile and flat colorectal polyps or laterally spreading lesions ≥ 20 mm were analyzed. The study period was from September 2008 to September 2016 and is registered as The Australian Colonic Endoscopic Resection (ACE) study (ClinicalTrials.gov NCT01368289 and NCT02000141). All lesions had been initially identified and referred by a nationally

Results

There were 2693 lesions assessed in the study period. One hundred and twenty-one lesions had missing histologic data, 89 lesions had incomplete Kudo classification data, 17 lesions had incomplete Paris classification data, 8 lesions had incomplete size data, and 15 lesions had incomplete surface morphology data. One hundred and fifty lesions had unclassifiable surface features, and 92 lesions had rare morphologic type (Paris IIb, III). Some lesions had more than one missing data type, so in

Discussion

The decision to undertake endoscopic resection of any colonic lesion hinges on the underlying risk of SMIC. For lesions with overt endoscopic signs of deep SMIC (Kudo V, Paris 0−IIc component), endoscopic resection is not recommended and surgical resection is favored unless there are compelling comorbidities that preclude surgery. Deep SMIC is associated with higher rates of lymph node metastasis, so even if endoscopic resection is successful, surgical resection and removal of locoregional

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    This article has an accompanying continuing medical education activity, also eligible for MOC credit, on page e16. Learning Objective: Upon completion of this CME activity, successful learners will able to (1) evaluate large sessile and laterally spreading colorectal lesions for risk of submucosal invasive cancer and (2) formulate an appropriate plan for management of these lesions.

    Conflicts of interest The authors disclose no conflicts.

    Funding The Cancer Institute of New South Wales provided funding for a research nurse and data manager to assist with the administration of the study. The Gallipoli Medical Research Foundation provided funding and support for research at Greenslopes Private Hospital. There was no influence from either institution regarding study design or conduct, data collection, management, analysis, interpretation, preparation, review, or approval of the manuscript.

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